新手问题！！输出指定范围 英文数字

[MYsce]

想要输出a 到 efg的范围内的英文字

例如
先输出a到 z
之后aa到zz
之后aaa 到efg
所有文字

[threenewbee]

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace T392469342
{
    class Program
    {
        static string incs(string s)
        {
            for (int i = s.Length - 1; i >= 0; i--)
            {
                if (s[i] < 'z')
                    return s.Substring(0, i) + ((char)(s[i] + 1)).ToString() + new string('a', s.Length - 1 - i);
            }
            return new string('a', s.Length + 1);
        }
        static void Main(string[] args)
        {
            string s1 = "efg";
            for (string s = "a"; s.Length < s1.Length || string.Compare(s, s1) <= 0; s = incs(s))
                Console.WriteLine(s);
        }
    }
}

[MYsce]

引用 1 楼 caozhy 的回复:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace T392469342
{
    class Program
    {
        static string incs(string s)
        {
            for (int i = s.Length - 1; i >= 0; i--)
            {
                if (s[i] < 'z')
                    return s.Substring(0, i) + ((char)(s[i] + 1)).ToString() + new string('a', s.Length - 1 - i);
            }
            return new string('a', s.Length + 1);
        }
        static void Main(string[] args)
        {
            string s1 = "efg";
            for (string s = "a"; s.Length < s1.Length || string.Compare(s, s1) <= 0; s = incs(s))
                Console.WriteLine(s);
        }
    }
}

谢谢

[xuzuning]

定义

        string BaseConvert(int n, char ch='a')
        {
            if (n < 26) return ((char)(n + ch)).ToString();
            return BaseConvert(n / 26 - 1) + ((char)((n % 26) + ch)).ToString();
        }

应用

            Console.WriteLine(BaseConvert(26)); //aa
            Console.WriteLine(BaseConvert(702)); //aaa
            Console.WriteLine(BaseConvert(3542)); //efg

你可以自己验证一下